In the south of Jena, two motorway bridges span the Saale valley. Already a few years after the construction of the first bridge towards the end of the 1930s, the non-functional rain spouts on its north and south sides were used as breeding sites by jackdaws (Corvus monedula) and kestrels (Falco tinnunculus). The breeding activity at the old Saale valley bridge was initially observed from 1949 to 1957. In the course of the renovation of the rain spouts, nesting boxes were installed inside the accessible bridge piers in 1972, which can be reached by the birds via existing light openings. As a result of the renovation of the motorway bridge and the new construction of the parallel second bridge, further nesting boxes were installed on the new bridge and on various buildings in the vicinity in 2018. Currently, 148 nesting boxes are available to the birds on both motorway bridges. This makes it the largest breeding colony of jackdaws in Thuringia, where monitoring has been carried out without interruption since 1973. During the nest box inspections, which are carried out at least twice a year, the occupation of the nest boxes, the clutch size and the number of fledged young birds are currently recorded. In addition, the fledging young birds are ringed. The data obtained provide valuable information on the population dynamics of the jackdaw in this breeding colony over several decades.